Advertisements
Advertisements
प्रश्न
Figure shows two processes A and B on a system. Let ∆Q1 and ∆Q2 be the heat given to the system in processes A and B respectively. Then ____________ .

विकल्प
∆Q1 > ∆Q2
∆Q1 = ∆Q2
∆Q1 < ∆Q2
∆Q1 ≤ ∆Q2
Advertisements
उत्तर
∆Q1 > ∆Q2
Both the processes A and B have common initial and final points. So, change in internal energy, ∆U is same in both the cases. Internal energy is a state function that does not depend on the path followed.
In the P-V diagram, the area under the curve represents the work done on the system, ∆W. Since area under curve A > area under curve B, ∆W1> ∆W2.
Now,
∆Q1 = ∆U + ∆W1
∆Q2 = ∆U + ∆W2
But ∆W1 > ∆W2
⇒ ∆Q1 > ∆Q2
Here, ∆Q1 and ∆Q2 denote the heat given to the system in processes A and B, respectively.
APPEARS IN
संबंधित प्रश्न
In changing the state of a gas adiabatically from an equilibrium state A to another equilibrium state B, an amount of work equal to 22.3 J is done on the system. If the gas is taken from state A to B via a process in which the net heat absorbed by the system is 9.35 cal, how much is the net work done by the system in the latter case? (Take 1 cal = 4.19 J)
When we rub our hands they become warm. Have we supplied heat to the hands?
Can work be done by a system without changing its volume?
In a process on a system, the initial pressure and volume are equal to the final pressure and volume.
(a) The initial temperature must be equal to the final temperature.
(b) The initial internal energy must be equal to the final internal energy.
(c) The net heat given to the system in the process must be zero.
(d) The net work done by the system in the process must be zero.
A 100 kg lock is started with a speed of 2.0 m s−1 on a long, rough belt kept fixed in a horizontal position. The coefficient of kinetic friction between the block and the belt is 0.20. (a) Calculate the change in the internal energy of the block-belt system as the block comes to a stop on the belt. (b) Consider the situation from a frame of reference moving at 2.0 m s−1 along the initial velocity of the block. As seen from this frame, the block is gently put on a moving belt and in due time the block starts moving with the belt at 2.0 m s−1. calculate the increase in the kinetic energy of the block as it stops slipping past the belt. (c) Find the work done in this frame by the external force holding the belt.
A substance is taken through the process abc as shown in figure. If the internal energy of the substance increases by 5000 J and a heat of 2625 cal is given to the system, calculate the value of J.

A gas is taken along the path AB as shown in figure. If 70 cal of heat is extracted from the gas in the process, calculate the change in the internal energy of the system.

A gas is initially at a pressure of 100 kPa and its volume is 2.0 m3. Its pressure is kept constant and the volume is changed from 2.0 m3 to 2.5 m3. Its Volume is now kept constant and the pressure is increased from 100 kPa to 200 kPa. The gas is brought back to its initial state, the pressure varying linearly with its volume. (a) Whether the heat is supplied to or extracted from the gas in the complete cycle? (b) How much heat was supplied or extracted?
When does a system lose energy to its surroundings and its internal energy decreases?
An ideal gas is compressed at a constant temperature. Its internal energy will ____________.
8 m3 of a gas is heated at the pressure 105 N/m2 until its volume increases by 10%. Then, the external work done by the gas is ____________.
Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Answer the following:
What is the final pressure of the gas in A and B?
Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Answer the following:
What is the change in the temperature of the gas?
Figure shows the P-V diagram of an ideal gas undergoing a change of state from A to B. Four different parts I, II, III and IV as shown in the figure may lead to the same change of state.

- Change in internal energy is same in IV and III cases, but not in I and II.
- Change in internal energy is same in all the four cases.
- Work done is maximum in case I
- Work done is minimum in case II.
In thermodynamics, heat and work are ______.
A gas is compressed at a constant pressure of 50 N/m2 from a volume of 10 m3 to a volume of 4 m3. Energy of 100 J is then added to the gas by heating. Its internal energy is ______.
The internal energy of one mole of argon at 300 K is ______. (R = 8.314 J/mol.K)
The molar specific heat of He at constant volume is 12.47 J/mol.K. Two moles of He are heated at constant pressure. So the rise in temperature is 10 K. Find the increase in internal energy of the gas.
Explain the change in internal energy of a thermodynamic system (the gas) by heating it.
